Keypad assembly with supplementary buttons and method for operating the same

ABSTRACT

Disclosed herein is a keypad assembly with supplementary buttons and method for operating the same. The keypad assembly with supplementary buttons is in a small-sized mobile communication terminal including input buttons for representing a plurality of characters and a plurality of function buttons. The keypad assembly has at least one mode switching button, at least one selection-indication button, and a control unit. The mode switching button is formed on a side of the terminal for switching an input mode for inputting different characters. The selection-indication button is formed on a side of the terminal for selecting and indicating one of a plurality of characters assigned to each input button. The control unit selects and inputs a specific character assigned to each input button by pressing the input buttons and the selection-indication button so as to select a specific input mode by pressing the mode switching button and select and input one of a plurality of characters assigned to a specific input button under the selected input mode. The control unit displays the selected and inputted data on a display window of the terminal and stores the data.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a keypad assembly withsupplementary buttons and method for operating the same, and moreparticularly to a keypad assembly with supplementary buttons and methodfor operating the same, in which there are provided a supplementary modeswitching button for switching the mode of a keypad and at least onesupplementary selection-indication button for selecting and indicatingone of a plurality of characters assigned to a single button insmall-sized terminals (for example, miniaturized, portable, and mobilecommunication terminals), so that various characters, such as alphabetcharacters, numerals, and special characters, can be inputted with onlya limited number of input buttons.

2. Description of the Prior Art

Generally, an input device of a terminal is used to interface a personwith a mechanical device, and is closely related to a person. Theterminal input device is included in electronic calculators, portablecomputers, mobile communication terminals, etc., and is closelyconnected with people's lives. Especially, the use demand forsmall-sized/portable communication terminals, which are convenient tocarry, rapidly increases. An input method in terminals is a method forallowing a machine to recognize the thought of a man. An input devicemostly utilizes a keypad (or keyboard) input method in which inputs arecarried out through a person's contact with the input device. In such akeypad input device, a plurality of buttons are installed in a limitedspace to input characters, so it frequently happens that severalcharacters must be inputted by one button. This is especially true ofminiaturized/portable terminals of a very restricted size.

As shown in the construction view of a conventional miniaturizedcommunication terminal of FIG. 1, since conventional small-sizedterminals, such as mobile telephones and Personal Digital Assistants(PDAs), are restricted by their physical sizes, it is impossible toinstall many buttons in a keypad within an input device. Accordingly, itis difficult to construct the buttons of the input device. In mostcases, it is only possible that the keypad has a few input buttons.

FIG. 1 shows a closed front view 110, a left side view 120, an openedfront view 130, a right side view 140, and a back view 150 of an exampleof a conventional terminal, which is based on character input buttons 13for representing numerals 0 to 9, alphabet characters A to Z, andspecial characters * and #, a plurality of function buttons 12, andother typical multiple functions. Further, referring to FIG. 1,reference numerals 11, 14 and 15 represent a display window, amicrophone, and a keypad, respectively. Here, the terminal of FIG. 1 istypical, and unimportant functions from the viewpoint of the presentinvention are omitted.

For the portable terminals, since many buttons cannot be installedespecially due to their restrictive sizes, mode switching operations areachieved by using the function buttons to input various characters, thatis, numerals, alphabet characters and special characters. Moreover, evenin a selected mode, inconvenient operations such as pressing the buttonsas many times as the number of characters assigned to any one button arerequired.

Further, the conventional portable terminals are problematic in that anassigned character is recognized by the number of presses of a specificbutton, such that the keypad must wait some delay time between thepressing operations. The construction of the keypad and its operatingmethod require the user to perfectly understand the functions of thekeypad. Further, the construction of the keypad and its operating methodcause the user confusion, are inconvenient in their manipulation, andcause the input speed to be decreased, due to the pressing of eachbutton several times for each operation.

As an example for solving these problems, a keypad formed in athree-layer structure such that one key can perform two operations byconstructing two contact points on the keypad is disclosed in KoreanPatent Application No. 1995-48201. In this keypad, each key signalsensing means is formed in upper and lower portions using thethree-layer structure, such that when the user presses the keypad, twoor more functions can be executed through one key by controlling theintensity of pressure exerted on a key. In this case, the intensity ofpressure exerted on a key can be well controlled with respect to such akeypad. However, if three or more characters exit on a single keybutton, three intensities of pressure must be distinguished from oneanother. Accordingly, character input errors may occur in the use of thekeypad.

Further, a keypad configuration produced to improve the accuracy inpressing keys by enhancing the height of a key, reducing the surfacearea of the key and increasing the space between keys is disclosed inKorean Patent Application No. 1997-11506. This keypad configurationprevents a user from pressing more than one key at a time, providesspace for alphabet characters beside each push button, and illuminatesthem, thus improving the visibility for characters and numerals.However, this keypad configuration only provides the convenience forpressing keys, while not providing convenience for mode switching ofcharacters or numerals and their input processes when a user inputs avariety of characters or numerals.

An example of an apparatus and method for selecting and inputtingcharacters is disclosed in Japanese Patent No. 1998-315522. The JapanesePatent discloses an apparatus and method for assigning similar characterand symbol groups to a plurality of preset specific positions in theinspection table of a plurality of characters and symbols composing asoftware and a keyboard, displaying the inspection list of assignedsimilar character and symbol groups when one key position of any onegroup at the specific positions is selected and indicated, and selectingone character or symbol of them to be inputted. The apparatus and methodmust display the inspection table of characters and symbols to beinputted, and the similar character and symbol group inspection listbased on the selection-indication. Therefore, the apparatus and methodhas limitation on application to small-sized terminals. Further, in theapparatus and method, characters represented on the keypad itself arenot selected and inputted, but the character and symbol groups displayedon a display window are inputted by selection-indication of aselection-indication means.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the prior art, and an object of the presentinvention is to provide a keypad assembly with supplementary buttons andmethod for operating the same, in which a supplementary mode switchingbutton for switching the mode of a keypad, and supplementaryselection-indication buttons for selecting and indicating one of aplurality of characters on a single button are installed on a keypad, aswell as a plurality of input buttons including typical telephone buttonsand function buttons, thus allowing a user to easily input characters,with only a small number of button presses.

In accordance with one aspect of the present invention, there isprovided a keypad assembly with supplementary buttons in a small-sizedmobile communication terminal including input buttons for representing aplurality of characters and a plurality of function buttons, comprisingat least one mode switching button formed on a side of the terminal forswitching an input mode for inputting different characters; at least oneselection-indication button formed on a side of the terminal forselecting and indicating one of a plurality of characters assigned toeach input button; and a control unit for selecting and inputting aspecific character assigned to each input button by pressing the inputbuttons and the selection-indication button so as to select a specificinput mode by pressing the mode switching button and select and inputone of a plurality of characters assigned to a specific input buttonunder the selected input mode, for displaying the selected and inputteddata on a display window of the terminal and storing the data.

In accordance with another aspect of the present invention, there isprovided a method for operating a keypad assembly with supplementarybuttons in a small-sized mobile communication terminal including aprocessor, input buttons for representing a plurality of characters anda plurality of function buttons, comprising the steps of a) forming atleast one mode switching button for switching an input mode forinputting characters and at least one selection-indication button forselecting and indicating one of a plurality of characters assigned toeach input button on a side of the terminal; b) switching an input modefor inputting characters using the mode switching button; c) pressing aninput button representing a character to be inputted in the switchedinput mode; d) selecting and indicating one of characters assigned toeach input button by pressing a corresponding selection-indicationbutton of at least one selection-indication button according to thesequence of characters assigned to each input button; and e) displayingthe selected and inputted data on a display window of the terminal andstoring the data.

The present invention relates to a keypad assembly with supplementarybuttons and method for operating the same, in which a mode switchingbutton and selection-indication buttons are additionally formed, therebyenabling a user to more easily input characters by using only a smallnumber of button presses.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a view showing the construction of a conventional small-sizedcommunication terminal;

FIG. 2 is a view showing the construction of a small-sized communicationterminal with supplementary buttons according to a preferred embodimentof the present invention;

FIG. 3 is a view showing one of character input buttons shown in FIG. 2according to a preferred embodiment of this invention;

FIG. 4 is a view showing the state transition of a user interface of thesmall-sized terminal with supplementary buttons according to a preferredembodiment of this invention;

FIG. 5 is a flowchart of a user interface process of the small-sizedterminal with supplementary buttons of this invention; and

FIG. 6 is a view showing the input operation of the small-sized terminalwith supplementary buttons according to a preferred embodiment of thisinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention is described in detail with referenceto the drawings based on the preferred embodiment of this invention. Thedrawings show a preferred embodiment of this invention, which isdescribed on the basis of a generally used mobile communicationterminal.

FIG. 2 is a view showing the construction of a small-sized communicationterminal with supplementary buttons according to a preferred embodimentof this invention. The same reference numerals are used throughout FIGS.1 and 2 to designate the same components. The communication terminals ofFIGS. 2 and 1 are very similar in their components and functions.However, they are different in that the terminal of FIG. 2 has aplurality of function and input buttons including typical characterinput buttons 13 representing characters such as “0 to 9”, “A to Z”, and“*”, and “#”, and a plurality of function buttons 12 as shown in FIG. 1,and it also has supplementary buttons installed on a right or left sideof the terminal, such as a mode switching button 20 and first, secondand third selection-indication buttons 17, 18 and 19. The mode switchingbutton 20 switches the input mode of a character table, and first tothird selection-indication buttons 17 to 19 select and indicate one ofseveral characters on any one button of the character input buttons 13or function buttons 12. FIG. 2 shows a closed front view 210, a leftside view 220, an opened front view 230, a right side view 240 and aback view 250 of the terminal in which the mode switching button 20, thethree selection-indication buttons 17 to 19 and the conventional buttonsare installed according to a preferred embodiment of this invention.Consequently, the difference between the terminals of FIGS. 1 and 2 isthat the supplementary buttons 17 to 20 are installed on the right (orleft) side of the terminal. In this case, the number of theselection-indication buttons can be changed. However, if a large numberof the selection-indication buttons are installed, even though thenumber of button presses for selecting and indicating one character canbe reduced to be convenient, the size and cost of the terminal may beadditionally increased, and its handling process may become complicated.On the other hand, if a small number of selection-indication buttons areinstalled, even though the size and cost of the terminal may be reduced,the number of button presses for selecting and indicating one characteris increased, thus resulting in inconvenience to the user.

Referring to FIGS. 2 and 3, the operations of the supplementary buttonsare described in detail. FIG. 3 is a view showing an example of oneinput button 300 of character input buttons 13 of FIG. 2. The characterinput button 300 is an input button on which a numeral “2” is assignedin a numeral mode, alphabet characters “A”, “B” and “C” in a alphabetcharacter mode, and special characters “@”, “#” and “$” in a specialcharacter mode.

The input button 300, as shown in FIG. 2, is one of a plurality ofcharacter input buttons installed on the keypad assembly of thisinvention, wherein the characters assigned to the input button 300 canbe changed. Operations of the mode switching button 20 and the threeselection-indication buttons 17 to 19 shown in FIG. 2 are describedusing the input button 300 of FIG. 3.

Switching operations among the numeral mode, the alphabet character modeand the special character mode are achieved by the mode switching button20. That is, the numeral mode is initially set, and if a user pressesthe mode switching button 20 once, the input mode is switched to thealphabet character mode. If the user presses the button 20 one moretime, the input mode is switched to the special character mode. If theuser presses the button 20 a third time, the input mode is switched tothe initial numeral mode. At this time, when the mode is switched, theswitching sequence can be randomly set. Therefore, whenever the userpresses the mode switching button 20 once, the input mode is switched.The initial input mode can be randomly set. The preferred embodiment ofthis invention is described by setting the initial mode to the numeralmode.

In the numeral mode, when the user presses the input button 300, thenumeral 2 is inputted. During the numeral mode, if the user pressesother character input buttons 13 of FIG. 2, set numerals are inputted.Since one numeral is assigned to each character input button 13, if theuser presses any one character input button 13, a numeral correspondingto the pressed button 13 is inputted.

Contrary to the numeral mode, in the alphabet character mode, eachcharacter is inputted using the above three selection-indication buttons17 to 19. Here, the characters are the alphabet. In the alphabetcharacter mode, after pressing the input button 300, if the user pressesthe first selection-indication button 17, an alphabet character “A” isinputted. At this time, if the user presses the secondselection-indication button 18, an alphabet character “B” is inputted,and if the user presses the third selection-indication button 19, analphabet character “C” is inputted. Alternately, the alphabet charactermode can be set such that, in the character mode, if the user pressesthe first selection-indication button 17 after pressing the input button300, the alphabet character “B” or “C” is inputted. It is preferablethat if the user presses the first to third selection-indication buttons17 to 19, characters in the left portion, the center portion and theright portion on the button are respectively selected to be inputted.

On the other hand, in the special character mode switched by the modeswitching button 20, each special character is inputted using the threeselection-indication buttons 17 to 19. In the special character mode,after pressing the input button 300, if the user presses the firstselection-indication button 17, “@” is inputted, if the user presses thesecond selection-indication button 18, “#” is inputted, and if the userpresses the third selection-indication button 19, “$” is inputted. Inthe special character mode, it is preferable that if a user presses thefirst to third selection-indication buttons 17 to 19, special charactersin the left portion, the center portion and the right portion on eachspecial character button are inputted respectively.

Therefore, the numerals, alphabet characters, and the special charactersare inputted by pressing the mode switching button 20, and the first tothird selection-indication button 17, 18, and 19. For example, when theuser desires to input “2 A C #”, the input mode is initially in thenumeral mode, such that if the user presses the input button 300, thenumeral “2” is inputted. Then, since “A” is an alphabet character, theinput mode must be switched to the alphabet character mode. Since thecurrent mode is the numeral mode, the input mode is switched to thealphabet character mode by pressing the mode switching button 20 once.In the alphabet character mode, if the user presses the input button300, and then presses the first selection-indication button 17, thealphabet character “A” is inputted. Then, if the user presses the thirdselection-indication button 19, the alphabet character “C” is inputted.Since “#” is a special character, the input mode is switched to thespecial character mode by pressing the mode switching button 20 one moretime. In the special character mode, if the user presses the inputbutton 300 and then presses the third selection-indication button 19,the special character “#” is inputted. Thereby, the above “2 A C #” areinputted.

The state transition of a user interface in the terminal using the modeswitching button 20 and the three selection-indication buttons 17 to 19is described with reference to FIG. 4.

FIG. 4 is a view showing the state transition of a user interface of thesmall-sized terminal with supplementary buttons according to thisinvention. The input modes are largely classified into a numeral mode22, an alphabet character mode 25 and a special character mode 35. Thetransition into each mode is circularly achieved by pressing the modeswitching button 20. The control unit 21 in which an input operationstarts in FIG. 3 inputs numerals by setting a basic input mode to thenumeral mode 22. Preferably, the control unit 21 is an alphanumericeditor. If only numeral patterns (23; “0 to 9”) are inputted in thenumeral mode 22, the mode is always in the numeral mode 22. At thistime, if a user presses the mode switching button 24 in the numeral mode22, the mode transitions to the alphabet character mode 25, such thatalphabet characters are inputted. If only alphabet character patterns(26; “A to Z”) are inputted in the alphabet character mode 25, the modeis always in the alphabet character mode 25. If the user presses themode switching button 34 in the alphabet character mode 25, the modetransitions to the special character mode 35, such that the specialcharacters can be inputted. If only special character patterns (36; !,@, #, . . . ) are inputted in the special character mode 35, the mode isalways in the special character mode 35. If the user presses the modeswitching button 44 in the special character mode 35, the mode returnsto the numeral mode 22. As described above, the mode switching iscircularly achieved by pressing the mode switching button 20.

The internal states in the numeral mode 22, the alphabet character mode25 and the special character mode 35 are described as follows. First,the internal state of the numeral mode 22 is empty, and noselection-indication button is used. That is, any of the threeselection-indication buttons 17, 18 and 19 is not used. Since onenumeral is assigned to each of the character input buttons 13, there isno internal state for the numeral mode. Contrary to this, for thealphabet character mode 25 and the special character mode 35, threealphabet characters or special characters are assigned to each button,such that there is use of the three selection-indication buttons 17 to19 in their internal states. In FIG. 4, pressings of the first to thirdselection-indication buttons 17, 18 and 19 are respectively representedby P1, P2 and P3.

If a specific input button (for example, the input button 300 of FIG. 3)is pressed, and then the first selection-indication button 28 ispressed, the alphabet character mode 25 transitions to a state 29, inwhich a first assigned character of characters assigned to the inputbutton is selected and inputted, such that the assigned character isselected. Further, if the second selection-indication button 30 ispressed, the alphabet character mode 25 transitions to a state 31, inwhich a second assigned character of characters assigned to the inputbutton is selected and inputted, such that the assigned character isselected. Further, if the third selection-indication button 32 ispressed, the alphabet character mode 25 transitions to a state 33, inwhich a third assigned character of characters assigned to the inputbutton is selected and inputted, such that the assigned character isselected. If the transitions of states 29, 31 and 33 for selecting andinputting each assigned alphabet character are completed and theselections are over, the internal state of the alphabet character mode25 automatically transitions to the button selection state 27 tocontinuously input alphabet characters.

On the other hand, if a specific character input button (for example,the input button 300 of FIG. 3) is pressed, and then the firstselection-indication button 38 is pressed, the special character mode 35transitions to a state 39, in which a first assigned special characterof special characters assigned to the special character input button isselected and inputted, such that the assigned special character isselected. Further, if the second selection-indication button 40 ispressed, the special character mode 35 transitions to a state 41, inwhich a second assigned special character of special characters assignedto the special character input button is selected and inputted, suchthat the assigned special character is selected. Further, if the thirdselection-indication button 42 is pressed, the special character mode 35transitions to a state 43, in which a third assigned special characterof special characters assigned to the special character input button isselected and inputted, such that the assigned special character isselected. If the transitions of the states 39, 41 and 43 for selectingand inputting each assigned special character are completed and theselections are over, the internal state of the special character mode 35automatically transitions to the button selection state 37 tocontinuously input special characters.

If an END button 45, which is a special function button, is pressed inthe numeral mode 22, the alphabet character mode 25 or the specialcharacter mode 35, an input end is executed, such that the keypad isescaped from the input state of the control unit 21.

As not shown in the drawings, the control unit 21 controls the aboveprocess, displays the data of the characters selected and inputtedthrough the above process on the display window of the terminal, andstores the data.

FIG. 5 is a flowchart of a user interface process of the small-sizedterminal with supplementary buttons of this invention. FIG. 5 shows theinternal recognition process of the user interface of the keypadassembly of this invention as an example using the specific input button300, the three selection-indication buttons 17 to 19, and the modeswitching button 20. This process is described with reference to theinput button 300 of FIG. 3 as an example of the character input button13. This entire process and its functions are controlled by the controlunit 21.

If the input control starts under the control of the control unit 21, aninitial mode state is set to the numeral mode (S501). Then, the modetransitions to the numeral mode 53 (S502). An arbitrary button ispressed in the numeral mode 53 (S503), and it is determined whether thepressed button is the input button 300 (S504). If the pressed button isthe input button 300, the input of the numeral “2” is recognized (S505),and then the processing step returns to step S502 so as to continuouslyinput numerals in the numeral mode. On the other hand, if the pressedbutton is not the input button 300, it is determined whether the pressedbutton is the mode switching button 20 (S506). If the pressed button isnot the mode switching button 20 according to the determination resultat step S506, the process ends, while if the pressed button is the modeswitching button 20, the mode state is set to the alphabet charactermode (S507) and transitions to the alphabet character mode (S508).

An arbitrary button is pressed in the alphabet character mode (S509),and it is determined whether the pressed button is the input button 300(S510). If the pressed button is the input button 300 according to thedetermination result of step S510, the processing step proceeds to anext step S511 and a selection-indication button is pressed (S511). Ifthe first selection-indication button 17 of the selection-indicationbuttons is pressed (S512), input of the alphabet character “A” isrecognized (S513). If the second selection-indication button 18 ispressed (S514), input of the alphabet character “B” is recognized(S515). Further, if the third selection-indication button 19 is pressed(S516), input of the alphabet character “C” is recognized (S517). Then,the processing step returns to the step S508 so as to continuously inputcharacters.

On the other hand, if the pressed button is not the input button 300according to the determination result of the step S510, it is determinedwhether the pressed button is the mode switching button 20 (S518). If itis determined that the pressed button is not the mode switching button20 according to the determination result at step S518, the process ends,while if the pressed button is the mode switching button 20, the modestate is switched from the alphabet character mode to the specialcharacter mode, such that the mode is set to the special character mode(S519). Then, the mode transitions to the special character mode (S520).

An arbitrary button is pressed in the special character mode (S521), andit is determined whether the pressed button is the input button 300(S522). If the pressed button is the input button 300 according to thedetermination result of step S522, the processing step proceeds to anext step S523, and a selection-indication button is pressed (S523). Ifthe first selection-indication button 17 of the selection-indicationbuttons is pressed (S524), the input of the special character “@” isrecognized (S525). If the second selection-indication button 18 ispressed (S526), the input of the special character “#” is recognized(S527). Further, if the third selection-indication button 19 is pressed(S528), the input of the special character “$” is recognized (S529).Then, the processing step returns to the step S520 so as to continuouslyinput special characters.

On the other hand, if the pressed button is not the input button 300according to the determination result of the step S522, it is determinedwhether the pressed button is the mode switching button 20 (S530). Ifthe pressed button is not the mode switching button 20 according to thedetermination result at step S530, the process ends, while if thepressed button is the mode switching button 20, the processing stepreturns to the step S501, such that the mode state is set to the numeralmode (S501) and transitions to the numeral mode (S502).

It should be noted that the end in each process for proceeding fromsteps S506, S518 and S530 to end steps can be set to transition to aninput exit state for operations not provided by the present inventionamong inputs of modes. However, such abnormal input processing can beset to transition to more intelligent processing states.

FIG. 6 is a view showing the input operation of the small-sized terminalwith supplementary buttons of this invention. That is, FIG. 6 shows anexample of the input operation for alphabet characters, numerals, andspecial characters using the user interface of the keypad assemblyaccording to a preferred embodiment of this invention. As shown in FIG.6 a, in the preferred embodiment of this invention, the user operatesthe mode switching button 20 and the three selection-indication buttons17 to 19 installed on the right side of the terminal while supportingthe small-sized terminal by the user's left hand, and operates thekeypad of the character input buttons 13 by the user's right hand. Inthis case, it is assumed that the basic input mode of the charactereditor in the control unit is the numeral mode. FIG. 6 b shows a tablerepresenting a process of inputting the input character string of FIG. 6a.

In order to display characters and numerals 101 of “VICTORY123” on thedisplay window 11, first the input mode, which is set to the numeralmode in current, must be switched to the alphabet character mode. Forthis operation, the input mode must be set to the alphabet charactermode by pressing the mode switching button 20. Next, a character “V” isinputted by combining and pressing the input button 103 representing “V”and the third selection-indication button 19. Then, a character “I” isinputted by combining and pressing the input button 104 representing “I”and the third selection-indication button 19. A character “C” isinputted by combining and pressing the input button 105 representing “C”and the third selection-indication button 19. A character “T” isinputted by combining and pressing the input button 103 representing “T”and the first selection-indication button 17. A character “O” isinputted by combining and pressing the input button 106 representing “O”and the third selection-indication button 19, and a character “R” isinputted by combining and pressing the input button 107 representing “R”and the second selection-indication button 18. A character “Y” isinputted by combining and pressing the input button 108 representing “Y”and the third selection-indication button 19. Therefore, “VICTORY” isinputted in the alphabet character mode. Next, the mode switching button20 for switching the input mode from the current alphabet character modeto the numeral mode is pressed so as to input numerals. Then, thecurrent input mode is switched to the numeral mode, and the numeral “1”is inputted by pressing the input button 109 representing the numeral“1”. Further, the numeral “2” is inputted by pressing the input button105 representing the numeral “2”, and the numeral “3” is inputted bypressing the input button 110 representing the numeral “3”. Therefore,“VICTORY123” which is the character-numeral string 101 is completelyinputted. On the other hand, the above procedures are processed by thecontrol unit of this invention and the control unit controls the overalloperating states of the present invention. The control unit ispreferably realized as a microprocessor.

Here, FIG. 6 shows an example for inputting alphabet characters andnumerals, however, it can be set to input special characters asdescribed above. This process can be achieved by realizing operationsfor representing numerals, alphabet characters and special charactersestablished on the input button of the keypad and processing them, and acontrol process switching algorithm, such as in the present invention.

Further, the process for restrictively inputting alphabet characters,numerals, and special characters is disclosed in the detaileddescription and drawings of the present invention. However, the keypadstructure, the operation method, and the control process switchingalgorithm of this invention can also be applied to the input of Koreancharacters. The alphabet characters and numerals are preferableembodiments of this invention for description, and do not restrict thescope of the present invention. Further, in the detailed description ofthe present invention, the character input process using thesupplementary mode switching button and selection-indication buttons isdisclosed. However, the character input process can be variouslyproduced according to the field, and can be used in pointing devices,direction buttons and a variety of other applications. Suchsupplementary buttons can be easily applied if the concept of thepresent invention is used.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

As described above, the present invention provides a keypad assemblywith supplementary buttons, in which the user's characterselection-indication can be easily achieved, and the keypad assembly hasan independent mode switching button, such that continuous operations ofswitching and inputting are accomplished by using the keypad structure,the operation method, and the control process switching algorithm ofthis invention.

Further, the present invention is advantageous in that it can reduce thenumber of presses for character input buttons and reduce the user'soperating confusion. The present invention can improve character inputspeed and eliminate input recognition delay by using a plurality ofselection-indication buttons. In this case, the present invention canremove the problem of waiting some delay time between button pressingoperations so as to recognize one character by a terminal.

Further, the present invention is advantageous in that it can be used aspointing devices, and direction buttons in electronic games, and it canbe effective in various other applications.

1. A key assembly with supplementary buttons in a small-sized mobilecommunication terminal including input buttons for representing aplurality of characters and a plurality of function buttons, comprising:at least one mode-switching button formed on a side of the terminal forswitching an input mode for inputting different characters; at least oneselection-indication button formed on a side of the terminal forselecting and indicating one of a plurality of characters assigned toeach input button; and a control unit for allowing a specific input modeto be selected by pressing the mode switching button, for allowing aspecific character to be selected and inputted by pressing the inputbutton and the selection-indication button in order to select and inputa specific one of a plurality of characters assigned to a specific inputbutton under the selected input mode, for displaying the selected andinputted data on a display window of the terminal and for storing thedata.
 2. The keypad assembly according to claim 1, wherein the modeswitching button is pressed, such that a numeral mode, an alphabetcharacter mode and a special character mode are circularly switched. 3.The keypad assembly according to claim 1, wherein each character isselected and inputted by pressing an input button representing acharacter to be inputted in the selected input mode, and then pressing aselection-indication button corresponding to the character.
 4. Thekeypad assembly according to claim 1, wherein the selection-indicationbutton is used in both an alphabet character mode and a specialcharacter mode.
 5. The keypad assembly according to claim 1, wherein theselection-indication button is formed to have the same number of buttonsas that of characters assigned to each input button.
 6. The keypadassembly according to claim 1, wherein the selection-indication buttonis formed to have the same number of buttons as that of specialcharacters assigned to each input button.
 7. The keypad assemblyaccording to claim 5 or 6, wherein the selection-indication buttoncorresponds to one character assigned to each input button.
 8. A methodfor operating a keypad assembly with supplementary buttons in asmall-sized mobile communication terminal including a processor, inputbuttons for representing a plurality of characters and a plurality offunction buttons, comprising the steps of: a) forming at least one modeswitching button for switching an input mode for inputting charactersand at least one selection-indication button for selecting andindicating one of a plurality of characters assigned to each inputbutton on a side of the terminal; b) switching an input mode forinputting characters using the mode switching button; c) pressing aninput button representing a character to be inputted in the switchedinput mode; d) selecting and indicating one of characters assigned toeach input button by pressing a corresponding selection-indicationbutton of at least one selection-indication button according to thesequence of characters assigned to each input button; and e) displayingthe selected and inputted data on a display window of the terminal andstoring the data.
 9. The method according to claim 8, wherein the modeswitching button is pressed, such that a numeral mode, an alphabetcharacter mode and a special character mode are circularly switched. 10.The method according to claim 8, wherein the selection-indication buttonis used in both an alphabet character mode and a special character mode.11. The method according to claim 8, wherein the selection-indicationbutton is formed to have the same number of buttons as that ofcharacters assigned to each input button.
 12. The method according toclaim 8, wherein the selection-indication button is formed to have thesame number of buttons as that of special characters assigned to eachinput button.
 13. The method according to claim 11 or 12, wherein theselection-indication button corresponds to one character assigned to theinput button.
 14. The method according to claim 11 or 12, wherein theselection-indication button corresponds to each character and eachspecial character on the input button.